Automatic fire-alarm.



No. 867,681. PATENTED OCT. 8, 1907.

' G. SMITH.

AUTOMATIC FIRE ALARM.

APPLICATION FILED JULY 9, 1907.

CHARLES SMITH, OF SOUTH OROYDON, ENG-LAND.

AUTOMATIC FIRE-ALARM.

Specification of Letters Patent.

Patented Oct. 8, 1907.

Application filed July 9,1907. Serial No. 382,856.

To all whom it may concern:

Z30 it known that I, ()uAnLns SMITH, a subject oi the King oi Great Britain, residing at South Croydon, in the county oi Surrey, England, have invented certain new and useinl Improvements in Automatic Fire- Alarms, and oi which the iollowiug is a specilication.

The obj ect oi this invention is to provide an improved automatically acting lire alarm, which shall operate by simple and reliable mechanical means, and shall not require any electrically conducting wires to extend through. the premises to be protected, and iurther shall be oi such construction that it can be titted with. little expense, is certain and prompt in its action in case oi tire, and is such that its reliability and effectiveness does not vary or d etcrioratc.

According to this invention the premises to be protected are titted with a ilexible cord, one end oi which is hrml y anchored to the wall at or near the ceiling or root, and continued around the interior oi the promises, being carried over pulleys where angles occur, and the cord is linally conducted to say near the entrance oi the building and is there connected with a pendent weight so that the cord is held .in tension; at intervals in the length oi the cord the latter is passed around the exterior surface oi one or more easily l'usible metal. members (which may be made in the iorm oi rings or disks) which are not lixed to the wall or to any other place, but are simply held suspended by the cord 'ng around their circumierence, the cord by so passing around the said l'usible members being shortened in its effective length, and such a iusible member can be litted wherever required by simply looping the cord around it.

The fusing point oi the metallic alloy (which is well known) and of which the iusible members are composed, is about 160 Fahrenheit, but they can be constructed, by regulating their thickness, to collapse at a much lower or at any desired temperature. It will thus be understood that upon a lire occurring in premso titted, one or more oi the iusible metal members will become solftened and collapse, and permit the llexible cord to be extended in length, and the weight to descend. I cause the descent oi this weight to compl ete an electric circuit and actuate an alarm, such as a bell ior instance, or the descent ol the weight may be caused to operate any convenient or well known mechanism which will automatically transmit an electric signal.

An example oi construction oi the invention is shown in the accompanying drawings, whereon Figure 1 is an elevation showing the flexible metallic cord anchored at one end, one oi the iusible members or rings around which the cord passes, and the weight suspended at the other end oi the cord adapted to complete an electric circuit and sound an alarm when the said weight descends. Fig. 2 is an elevation, Fig. 3 is a plan, Fig. l a vertical transverse section, and Fig. 5 is a perspective view oi the construction 01' one oi the iusible metallic rings which I employ having ears to retain the flexible cord in position.

The flexible metallic cord 1 employed in this invention may suitably be composed oi a number oi strands laid as usual, and may be oi phosphor bronze with a minimum breaking strain oi l'or instance about 100 lbs, and one end 2 oi the cord 1 is lirmly iixed to a wall such as 3, by means oi a wall plate at having a stud 5. The cord 1 extends around or through the room or rooms to be protected, passing, where angles occur, over suitable pulleys or lixed guides, and the opposite end oi the cord is passed over a pulley 6 and carries at its end a weight 7.

In the diagrammatic drawing, Fig. l, the end oi the flexible metallic cord 1 is connected to a small length oi chain 8, where it passes downwards over the pulley, but this is not necessary, as I have iound that the metallic cord can be obtained in commerce with suilicient flexibility to pass over the pulley. The weight, in the diagram view shown, is caused upon its descent to con nect two contact studs 9, and so complete an electrical circuit 10 and sound an alarm bell 11.

At any required number oi points in the length oi the cord 1, I place one oi the iusible metallic rings 12, the ring 12 being supported by the cord 1 being passed once around its circumierence, and then upon the fusible metal ring 12 becoming suiliciently softened or melted (which can be caused to occur at a temperature oi about 140 to 160 Fahrenheit) the cord will be extended in length by the action of the weight 7, and consequently the weight will fall and complete the electric circuit and give the necessary indications that a the has occurred.

In constructing the rings, it is desirable that means should be provided to prevent the flexible cord I accidentally slipping off, and to this end I iorm cars 13 (Figs. 2 to 5) extending radially from the outer periphery of the ring, and each ear is formed with a hole near its base extending in the plane oi the annulus, and a slot 14such as a saw-cut-is iormed in the top oi the ear to communicate with the hole, this slot being at an angle to the plane oi the annulus. With such a construction oi l'usible member 12, the cord 1 can be given one turn around the periphery oi the ring 12, so that the cord 1 passes, by way oi the slot 14, into the hole formed through each ear. There are three cars shown in the drawing, and thereiore the cord passes singly through two oi such ears, while the hole through the third ear would contain two strands oi cord as shown at Fig. 3, one passing in the direction 01' the stationary stud 5, and the other towards the weight 7.

By the construction of the l'usible member in the form shown at Figs. 2 to 5, I have found by experiment that the effect of the heat acting upon the same is firstly to soften the ears 13, and then the tendency is for the tensioned cord to force off the two parts of an ear sidewise in opposite directions; the ring then falls away, and the loop of the cord opens out and can be stretched into a straight line without kinking. Thus I do not depend for the action upon the mere expansion of the metal composing the cord, but upon the fusing of the ring 12, or of some part of it, and to some extent upon the flexibility of the metallic cord in proportion to the weight 7 by which it is stretched.

From the foregoing description it-will now be clear that any number of the fusible rings at any required distances apart can be placed upon a flexible metallic cord (which is already fixed in position) by simply passing the cord once around each member, and infact, if so desired, the members can be adjusted upon the cord as to distance apart, by simply moving them along and allowing the cord to pass around their circumference.

The form of construction of the invention which has been described, where each fusible member is made in the shape of a ring, is of advantage, because the thickness of the rings can be varied and the time elapsing between the outbreak of a fire and the giving of the alarm thereby varied, while the particular form of construction of the rings shown having ears, permits the cord to pass away from the rings, or the rings to pass away from the cord, and the cord to be extended or straightened without twisting or kinking.

What I claim as my invention and desire to secure by Letters Patent is:

'1. In an automatic fire alarm; the combination with a flexible cord, a fusible metallic member around the ex ternal periphery of which the cord passes to support said member and to reduce the effective length of said cord until said member becomes fused, means for holding the said cord in tension, and means for completing an electric circuit by the extension in length of said cord when said member is fused, substantially as set forth.

2. In an automatic fire alarm; the combination with a flexible cord, means for holding one end of said cord stationary, a pendent weight connected to the opposite end to hold said cord in tension, stationary electric contact studs adapted to be electrically connected by said Weight to complete an electric circuit when said weight descends, and an alarm device in said circuit; of a fusible metallic member, around the external periphery of which the cord passes to support said member and to reduce the effective length of said cord until said member becomes fused and thereby permits said weight to descend, sub stantially as set forth.

3. In an automatic fire alarm; the combination with a flexible cord, means for holding one end of said cord stationary, a pulley over which the opposite end of the cord passes, a pendent weight connected to the latter end of the cord to hold the said cord in tension, stationary electric contact studs adapted to be electrically connected by said weight to complete an electric circuit when said weight descends, and an alarm device in said circuit; of

a fusible metallicmember located between the fixed end of the cord and the pulley at the weighted end, and around the external periphery of which member the cord passes to support said member and to reduce the effective length of the cord until the said member becomes fused, and permits said weight to descend, substantially as set forth.

4. In an automatic fire alarm; the combination with a flexible cord, means for holding one end of said cord stationary, a pendent weight connected to the opposite end to hold said cord in tension, stationary electric contact studs adapted to be electrically connected by said weight to complete an electric circuit when said weight descends, and an alarm device in said circuit; of a ring of metallic alloy fusible at a comparatively low temperature, around the external periphery of which ring said cord passes to support the said ring and to reduce the eltective length of said cord until said ring becomes fused and thereby permits the said weight to descend, substantially as set forth.

5. In an automatic fire alarm; the combination with a flexible cord, means for holding one end of said cord stationary, a pendent weight connected to the opposite end tohold said cord in tension, stationary electric contact studs adapted to be electrically connected by said weight to complete an electric circuit when said weight descends, and an alarm device in said circuit; of a ring of metallic alloy fusible at a comparatively low temperature, around the external periphery of which ring said cord passes to support the said ring and to reduce the elTective length of said cord until said ring becomes fused and thereby permits said weight to descend, and means for retaining said cord upon the periphery of said ring, substantially as set forth.

6. In an automatic fire alarm; the combination with a flexible cord, means for holding one end of said cord stationary, a pendent weight connected to the opposite end to hold said cord in tension, stationary electric con tact studs adapted to be electrically connected by said weight to complete an electric circuit when said weight descends, and an alarm device in said circuit; of a ring of metallic alloy fusible at a comparatively low temperature, radial ears extending from the outer periphery of said ring, each of said ears having a hole formed through it near its base in the plane of the ring, and having a slot extending from the top of the ear to the hole to permit said cord to pass into said hole through said slot of each ear as said cord is passed around the periphery of the ring to support the latter and to reduce the effective length of said cord, the hole of one of said ears containing two strands of said cord, one passing in the direction of the pendent weight and the other in the direction of the holding means, substantially as set forth. In witness whereof I have hereunto set my hand in the presence of two witnesses.

CHARLES SMITH.

Witnesses THOMAS W. ROGERS, WILLIAM A. MAnsHALL. 

